Usability testing with children is similar in many respects to usability testing with adults. In order to get the most out of the sessions, and ensure the child is comfortable and happy, there are a few differences that you need to be aware of.

Stress of new people and surroundings 

Children are far more likely than adults to find encountering new places and people stressful. You should always remember this, so try to find as many ways as possible to relax the child. Some things you could do are:

- Allow a significant period of time - at least 10 minutes - to meet the child. This is critical in putting them at ease before beginning the session. Some easy things to talk about might be computer games, cartoons, sports or school. Trying to make all the equipment used during the session match that which the child uses at home/school (phone up their parents/teachers beforehand to check).
- Try to be as comforting and reassuring as possible. It's especially important to make it clear to the child that you want their views on the site and that you're not testing them.
- Plan for the fact that younger children may prefer their parents to remain in the testing room with them. Make sure that parents know that they should stay out of the child's line-of-sight and not help or distract them. 

Asking for help 

Children are far more used to asking for - and receiving - help than adults, so it's very important for the moderator to:

- Clearly explain at the beginning of the test that you want the child to use the site on their own
- Make a sustained effort to deflect any such questioning during the session itself 

Good ways of deflecting questions can include:

- Answering a question with a question (e.g. What do you think [you should do now]?)
- Re-stating that you want the child to use the site ‘on their own’
- Asking the child to have ‘one last go’ before you move on to something else 

Children get tired, bored and discouraged more easily 

Children (especially of younger ages) are less inclined - and/or able - to apply themselves to a single task for a prolonged period. Some ways to work around this are:

- Limiting sessions to 1 hour or less.
- Taking short breaks during sessions if the child becomes tired or irritable.
- Ensuring that sessions cover the intended tasks/scenarios in a different order - this will make sure that the same scenarios are not always tested by tired children, who are less likely to succeed/persevere.
- Asking the child for help so as to provide them with motivation (e.g. asking ‘Could you please find out for me how to...’, or by actually pretending to not be able find/do something on the site).
- Keeping up a steady stream of encouragement and positive feedback (“You're doing really well and telling us lots of useful things - it will really help make the site better. Keep it up!”). 

The importance of non-verbal cues 

Children can't always be relied upon to verbally articulate their thoughts/feelings, either due to their:

- Not being articulate enough
- Being too shy
- Not wanting to say the wrong thing and displease an adult
- Saying things they don't believe just to please the adult 

This makes it particularly important that the usability expert be sensitive to children's non-verbal cues, such as:

- Sighs
- Smiles
- Frowns
- Yawns
- Fidgeting
- Laughing
- Swaying
- Body angle and posture 

Physical differences 

A couple of very obvious - but easily forgotten - differences which need to be taken into account are:

- Chair and table settings - Make sure you have a chair/table setting that allows the child to comfortably use the equipment during the session.
- Microphone positioning - Children tend to have quieter voices than adults, so microphones should be placed slightly nearer to the participant than normal. 

Levels of literacy and understanding 

It is critical to ensure that a session's participant has an accurate understanding of the scenario being presented to them. Some ways to do this include:

- Asking participants to re-phrase scenarios/goals in their own words.
- Asking participants to repeat a scenario (i.e. what they are trying to achieve) if the task has gone on for some time and you suspect they may have forgotten it. 

This article was written by Tim Fidgeon, Head of Usability at Webcredible. He's crazy about usability and runs Webcredible's writing for the web training and is passionate about user centered design.